The present invention is related to a wind park and to a method for the operation of a wind park. The wind park has a plurality of wind energy plants, which each have one plant control. The plant control is able to preset the active power to be generated by the wind energy plant, provided that there is enough wind. For this purpose, a desired value is preset to the plant control of the wind energy plant. The plant control can be also realised as a closed-loop control, so that the actual value of the active power generated by the wind energy plant can be regulated to the desired value. Further, the wind park is equipped with a park control, which presets a desired value for the active power to each plant control.
From WO 01/25630 A1, the entire contents of which is incorporated herein by reference, a wind park is known, the power rating of which is greater than the power which can be fed and/or is permitted to be fed into the power supply grid to which the wind park is connected. In order to limit the power which is fed to the maximum value, it is proposed to limit the fed power of all the wind energy plants of the wind park.
From WO 03/030329 A1, the entire contents of which is incorporated herein by reference, a wind park is known, the active power delivered into the power supply grid of which can be preset by a grid operator. The control of the wind park reduces the output for the wind energy plants according to the defaults, wherein the output thereof can be throttled equally or differently at a time.
From GB 2 330 256 A, the entire contents of which is incorporated herein by reference, a wind energy plant is known, in which the voltage is measured at the connection point of the wind energy plant to the grid and the maximum possible power to be fed is calculated. An overvoltage through the power which is fed into the grid by the wind energy plant is to be avoided at relatively weak grid connections in particular.
From EP 1 467 463 A1, the entire contents of which is incorporated herein by reference, a wind park is known, which has a park control. The active power fed into the grid by the wind park is adjusted depending on the frequency measured at the grid connection point. This control/closed loop control for the wind park is based on the fact that when more power is generated than consumed in a grid, the frequency increases, and the frequency then decreases when more power is consumed than is generated.
From EP 1 571 746 A1, the entire contents of which is incorporated herein by reference, a method for the closed-loop control of the active power in a wind park is known. The method provides that a desired value for the active power of the park control can be preset manually or dynamically. In the case in which the actual value of the power exceeds the desired value, two methods are provided in order to reduce the surplus power of the wind park. In the first concept, the power is run up to a maximum value for selected wind energy plants, and the remaining other plants are scaled down. In an alternative concept, one or several wind energy plants are scaled down and the fine adjustment of the power is performed by the remaining plants.
It is known that under certain grid conditions and/or when certain grid errors occur, it may happen that the power fed into the grid by a wind park has to be limited within a short period of time and has to be stably maintained on the limited value. Usually the signal which triggers this process in the wind park is preset by the grid operator. The period of time within which the active power has to be scaled down is less than 4 seconds, for instance.
The present invention is based on the objective to provide a wind park and a method for the operation thereof, which permits with simple means to limit the active power fed into electric grid within a short period of time, without limiting the possibilities for the closed loop control of the wind park.